Data is written/read across two or more drives simultaneously, effectively allowing it to be accessed much more quickly. It allows all the hard drives in the RAID array to appear as a single device with the total combined storage of all the drives. E.g. two hard drive of 256GB and 512GB, would appear as a single 768GB drive. This form of RAID is sometimes called striping and does not provide any extra redundancy than storing your data to a single hard drive. If one drive fails and is then replaced, the other can not rebuild the whole data file.

Two or more disks are used to store the data as exact images of the other. As data is being written or read from one disk the RAID controller “mirrors” this data to the other drive/s. This provides a high level of redundancy as if one drive fails the other has a full working set of data. However, it means that you would only be able to have as much storage space available as the size of the smallest disk in the RAID array. E.g. two hard drive of 256GB and 512GB, would appear as a single 256GB drive.

A combination of RAID 0 and RAID 1, data is distributed across multiple drives without parity, and then the entire array is mirrored. Although this delivers good performance, the drive storage overhead is 50% because you are mirroring the data.

Data is striped at a block level across several drives, with parity stored on one drive. The parity information allows recovery from the failure of a single drive. The performance of RAID 4 is very good for reads. Writes, however, require that parity data be upgraded each time. This slows down random writes in particular, though large write or sequential writes are fairly fast.

Employs data striping and parity across all drives in the array creating better performance and security. Since parity information is striped across all drives, lost data can be retrieved and rebuilt from the parity.

Definition: The ability and means to communicate with or otherwise interact with a system, to use system resources to handle information, to gain knowledge of the information the system contains, or to control system components and functions.
From: CNSSI 4009

Definition: Security measures designed to detect and deny unauthorized access and permit authorized access to an information system or a physical facility.
Adapted from: CNSSI 4009

All-flash storage array is running SAN or NAS protocols on a set of controllers and is best when optimized software is engaged to take advantage of all enterprise SSD drives allowing quick IOPs and throughout.  All-flash systems will not run spinning hard drives and must be all SSDs.   

A list of entities that are considered trustworthy and are granted access or privileges.
Related Term(s): Blocklist
Adapted from: DHS personnel